Clutch specs

[67D100Pickup]

If I have my transmission off because of an engine rebuild, should I put a new clutch on? How do I tell how much life is left in the existing clutch plate? I don't want to spend the $200 of its already a like-new clutch.

Jeff

[Jim100]

Maybe at least a throw out bearing?

[67D100Pickup]

Yes. I was hoping someone might know the depth of a new clutch plate so I could measure it.

[Hobcobble]

For the price of a new disc, pressure plate, pilot bushing and throw out bearing, I'd
just put them all in, seeing as the tranny is out of the truck now. This way, you know
you're starting out with all new components. Just my opinion.....

John

[wally426ci]

I agree with John. BIG PITA to yank it all again when you hear a "new" noise....

[Kaegi]

the friction material on each side of disk when new is about .125' from rivets to surface on the 10 inch and gets a little thicker on larger clutches. if your not close to the rivets no reason to change the disk. inspect the flywheel and pressure plate for heat cracks and hard spots. hard spots look like fish eye a little and can cause chattering. if you sand the flywheel with 80 you will see any problems.

[67D100Pickup]

Gotcha. I need a new plate.

Thank you very much!

[67D100Pickup]

For the price of a new disc, pressure plate, pilot bushing and throw out bearing, I'd
just put them all in, seeing as the tranny is out of the truck now. This way, you know
you're starting out with all new components. Just my opinion.....

John

Understood. Almost everyone agrees with this. I did get some specs on it though and confirmed I need a new plate. It feels better *knowing* I need one.

Thank you.

[67D100Pickup]

OK. It's been two years now since I had the clutch rebuilt with new material, had the flywheel machined and installed with a new throwout bearing. It has never been right since.

First, the thing would pound like hell when I released the clutch. I discovered that was because the throwout bearing had not been pressed completely in, it was literally crooked but I wasn't observant enough to see that before I installed it. I returned it to City Brake & Clutch and they pressed the bearing the rest of the way in and I reinstalled it. It worked almost "normal" but it still pounded a little when released and made a noise when the clutch was fully released. Obviously a bad thing. I since adjusted it so there is play when the clutch is fully released. I'm pretty sure it isn't being depressed by the pedal/linkage/hydraulics any more when released.

I've driven it for two years now (maybe a few hundred miles) and the noise is getting worse - no surprise.

I'll replace the throwout bearing with a new one now but the clutch slips so I have another question... .

Could a bad throwout bearing cause this? I did rebuild to engine to around 300 HP and put a limited slip differential in it with 272 gears so I don't know if I should have upgraded the clutch? Stiffer springs? Switch to ceramic?

Jeff

[nutz]

272 is a little high for manual trans
noise when out is either the throw-out lightly hitting the clutch forks or your input bearing in your trans or just a worn bearing
ceramic clutches are hard to drive ,they don't like to slip ,so its on or off
and with a high gear ratio is going to be hard to get it rolling on a hill
you did the pressure plate too ?

[67D100Pickup]

Yes, they did the pressure plate too. I'll definitely nix the ceramic clutch idea but I do want to stop the slipping at full throttle.

Note that it does not slip if I let the clutch fully engage before adding throttle. It only slips if I release the clutch with heavy throttle but it doesn't grab quickly; it seems to slip too much before it fully engages. I expected it to grab completely once I release the pedal, even at high throttle, yes?

Jeff

[nutz]

yes should "lock in"
was thinking might be the pressure plate release travel
not sure what type of pressure plate you have .. is it the one with 3 release forks thats the one that you can change the springs there might be
an adjustment on the angle of the release forks ,that would effect the rate of engagement
if its a finger clutch than it just install and go
that being said if the clutch got glazed its toast

[67D100Pickup]

Yes, it's got three prongs. Stronger springs sounds like a good answer. Not sure how to go about that, how to find the right spring to put in it, etc.

Jeff

[nutz]

never played with one
just remember when i was in school there was something about setting up clutches
but that was 40 years ago and it was hd trucks

[67D100Pickup]

yes should "lock in"
was thinking might be the pressure plate release travel
not sure what type of pressure plate you have .. is it the one with 3 release forks thats the one that you can change the springs there might be
an adjustment on the angle of the release forks ,that would effect the rate of engagement
if its a finger clutch than it just install and go
that being said if the clutch got glazed its toast

Ok. I want to let HR Clutch rebuild this clutch with stronger springs and they want to add double friction plates, whatever that means. But I have a concern about the diaphragm spring fingers. It has three but they are not even. One sits further back/down than the other two when the clutch is off the truck. I think this is causing it to lurch as I engage the clutch and I don't think a rebuild is going to fix that part of the problem.

If HR Clutch can adjust those it seems ok but if they can't, I'll need a replacement diaphragm spring or fingers, right?

Jeff

[PwrWgnDrvr]

.

[nutz]

all the levers should be even
more so when compressed
so duel friction ? or duel plates
don't want to aggressive friction material or it will be hard to drive

[Wildergarten]

For the price of a new disc, pressure plate, pilot bushing and throw out bearing, I'd just put them all in, seeing as the tranny is out of the truck now.

And surface the flywheel. And I should remember to check the date on the post.

[Kaegi]

if the levers are not even they didnt rebuild it right. they need to be set to an exact spec! all the springs should be the same color. they stiffness of the springs are color coded. i had one done where they mixed up springs and it was not even drivable.